Data Sheet 1_Immunohistochemical and western blot expression of MMPs, TIMPs, and cytokeratin 10 in feline squamous cell carcinoma.docx

BackgroundFeline oral and cutaneous squamous cell carcinoma (SCC) are aggressive neoplasms characterized by high local invasiveness. Given its spontaneous occurrence and molecular similarities, feline SCC represents a robust comparative model for human head and neck squamous cell carcinoma (HHNSCC). This pilot study aimed to characterize the expression of metalloproteinases (MMPs), their tissue inhibitors (TIMPs), and cytokeratin 10 (CK10) in relation to Papillomavirus (PV) status, and to explore the viral-molecular relationship in feline oncology.
MethodsTen feline SCC samples (3 oral and 7 cutaneous) were analyzed. PV DNA was detected using PCR with degenerated primers FAP59/FAP64. Protein expression of MMP-2, -9, -13, -14, TIMP-2, -3, and CK10 was analyzed and quantified via immunohistochemistry (IHC) (H-score) and validated through Western blot analysis. Statistical correlations were determined using the Spearman rank correlation coefficient, and statistical differences between groups were assessed via Mann–Whitney U test.
ResultsPV DNA was identified in 6/10 samples. IHC analysis revealed that MMPs (-2, -9, -13, -14) exhibited stronger cytoplasmic and nuclear immunostaining compared to the more restricted signals of TIMPs and CK10, showing a strong inverse correlation with MMP-2, linking invasiveness to dedifferentiation. Significant positive correlations were found between MMP-9/TIMP-3 and MMP-2/MMP-9. TIMP-2 expression was significantly higher in PV-negative samples. Western blot confirmed these results, showing consistent bands.
ConclusionThis pilot study provides the first characterization of MMPs, TIMPs, and CK10 in feline SCC, establishing a foundation for future research into feline PV species and reinforce the value of the feline model in comparative oncology.